Can my AirPort Extreme work via a Cat5 ethernet port within my network? I ask because we've had no luck doing this where as our older Airport Express works just fine this way. Thoughts? We upgraded to the Extreme to extend the signal (and have 2 antennas) and trying to avoid hooking it up to the cable modem box which is even further away than where the Airport Express was located. Thanks for any help. I'm sure this is a basic and simple problem.